Few hours fiddling with code this afternoon.
Have dropped brightness to 1/32 of full power! Doesn't leave a lot of room for going dimmer.
Deciding how to actually display the time is quite tricky in itself. I have an inner ring with 12 leds and outer with 24, so maybe display hours on the inner ring and 2.5 min intervals on the outer? Hmm.
Thought about using wider 'hands' like using 3 pixels for the hour hand and fading brightness but it seems ambiguous and I want to be able to tell the time at a glance.
Haven't broken out the RTC yet, but was trying to approximate a 1 sec sweep around the outer ring. 1000/24 is 41.66 so I tried using that as a delay value - way too fast. Trial and error led me to a value of 80ms, I'm not sure why this works.
Evidently delay isn't suited to task unless you know how it takes to do everything else and I should look at millis() for more accuracy.
Not going to worry too much about this, more concerned with how to see if I'm getting useful anything from the RTC (Trinket has no Serial for debugging)
12sec timer (approx!):